Air distribution system



P 27, 1955 w. L. M GRATH I 3,275,068

' AIR DISTRIBUTION SYSTEM Original Filed Jan. 18, 1962 5 Sheets-Sheet l[,5] I FIG. I

: I I I 3: 0 D w Ii O. O 5 INVENTOR. E WILLIAM L. MC GRATH. I5 BY c. F.m.

ATTORNEY.

Sept. 27, 1966 w, NICGRATH 3,275,068

AIR DISTRIBUTION SYSTEM Original Filed Jan. 18, 1962 5 Sheets-Sheet 2 55j F|G.2

V --v-]I mi 1 I 5o 22 I f I INVENTOR.

"" WlLLlAM L. MCGRATH;

ATTORNEY.

Sept. 27, 1966 w. L. M GRATH AIR DISTRIBUTION SYSTEM 5 Sheets-Sheet 5Original Filed Jan. 18, 1962 MC GRATH.

INVENTOR.

WILLIAM L ATTORNEY.

United States Patent 3,275,068 AIR DISTRIBUTION SYSTEM William L.McGrath, Syracuse, N.Y., assignor to Carrier Corporation, Syracuse,N.Y., a corporation of Delaware Original application Jan. 18, 1962, Ser.No. 167,106, now Patent No. 3,163,100, dated Dec. 29, 1964. Divided andthis application Nov. 9, 1964, Ser. No. 409,904 2 Claims. (Cl. 16531)This application is a division of my copending application Serial No.167,106,, filed January 18, 1962, now Patent No. 3,163,100 issuedDecember 29, 1964, and relates to air conditioning, more. particularlyto means for selectively adjusting thedistribution of conditioned air toconditioned areas, without-interfering with the operation of the'airconditioning system.

A variety of equipment has been evolved serving to maintain the air inany given area. under desired temperature, humidity, and-purityconditions. This is generally accomplished by suitably treating the airin the conditioned area by means of heaters, refrigeration equipment,humidifiers and/ or air purifiers of a variety of types functioning'alone or in combination. After suitable treatment, the conditioned airis distributedto the conditioned area viasuitable supply ducts throughregisters which function to control air distribution paths and velocityinthe conditioned area. It is also desirable to recirculate some of thepreviously conditioned room air admixing it with newlyconditioned air toobtain desiredair change and air movement.

Where a central air conditioning system is employed to provide air ofdesired characteristics to a variety of different remotely locatedareas, conditions in these remotely located areas may vary sufiicientlyso that different occupants of different areas will requiredifferentrates of air conditioning. Thus where a centrally located refrigerationsystem is employed to control air for distribution to different rooms ofa building, the occupants of a room exposed to the sun or some otherheat load would require a greater rate of cooling than those in rooms inshaded portions of the building. As is apparent, a happy medium ofrefrigeration system operation or heating system operation such as willplease the occupants of different parts of the building Will not oftenbe attainable.

Individual control of the air conditions in a given area to which air isfed from the air conditioning equipment is often controlled bycontrolling the flow of, air to these areas. Thus a heating or coolingcoil is positioned in a duct through which air is directed to thevarious areas to be conditioned. Dampered outlets at these areas permitthe occupants to control the flow of air to. the conditioned area byadjustment of the damper; at the outlet. found, however, that conditionsoften arise where enough of the outlets from the air supply ducts areclosed sothat there is a rise in static pressure within the duct and aresultant decreasein flow'of air over the-heating or cooling surfaces.The resultant decreaseinair [flow over the heat-.

ingor cooling surfaces resultsin an imbalance within therefrigeration-or heating system due to a lack of required heat exchangebetwen the heat-transfer medium and the air.

It is with the above problems and. desiderata in mind that the presentmeans have been evolved,- means apparatus serving to permit theindividual control of air distribution from air conditioning equipmentto a conditioned area in which the occupant of the conditioned area mayselectively determine the quantities of conditioned air providedwithoutinterfering with the functioning of. central air conditioningequipment utilized to condition air for other areas.

-It is accordingly an object of this invention to provide improved meansfor controlling air distribution from air conditioning equipment. Itwill be understood by those skilled in theartthat the term airconditioning includes heating, cooling, humidifying, dehumidifying andair purifying, whether for industrial. or comfort purposes.

A further object of ,the invention is to provide improved means forcontrolling air distribution from a central conditioning point at avariety of different distribution points with the control actionprovided at any one distribution point not adversely affecting theoperation of the conditioning equipment. I

It is an additional object of the invention to provide a novel airdischarge register serving to implement the distribution of conditionedair, and the admixture of return air from the conditioned area with theconditioned air stream.

A further object of the invention is to provide improved means formaintaining desired air pressures in the air conditioning ducts adjacentthe heat exchangers of the cooling or heating equipment employed forconditioning the air flowing through said ducts so asto insure desiredair flow over the heat exchangers, and thereby to maintain desired heatexchange through the heat exchanger surface.

Another object of the invention is to provide improved means for manualselective control of conditioned air distribution in any conditionedarea by the occupants thereof.

These and other objects of the invention which will become hereafter.apparent are attained by provision of a novelregister construction andmode of operation for use at the outlet points of the distribution ductsof an air conditioning system. Thus a duct extends from the heating orcooling coils of the air conditioning equipment to the conditionedareas. The novel register is positioned in these areas to providedesired design conditions. This register comprises a yieldably mounteddamper plate selectively movable within the duct to adjustably constrictthe flow of air through the duct. A return air inlet is formed intheregister to permit air from the conditioned. area to be induced forflow through the register with the conditioned air. The yieldable dampermounting is such that as the static pressure in the duct builds up abovea desired design level as determined by the conditions necessary toobtain efficient functioning of the heating or cooling coil, the 'baflieplate or damper will be displaced to permit air flow through the duct toobtain the desired design pressures. A control knob suitably positionedin the conditioned area is coupled via a control assemblyincluding arack and a pinion for movinga control rod which acts on the crank of ashaft coupled by a spring clutch to a shaft on which the damper-issupported.

An important feature of the invention resides in the novel yieldablemounting for the damper plate which permits selective. opening orclosing of the register by the occupants of a conditioned area but isresponsive to abnormally high pressure conditions in the duct therebyopening the register to provide desired air flow past the heatexchangers in theduct.

Another feature of the invention resides in the arrangement of thebafile plate or damper whereby the quantity of air recirculated from theconditioned. area is inversely proportional to the quantity ofconditioned air supplied. Thus, the damper is so arranged that as it ismoved to constrict the duct, the air velocity emerging from the registerincreases, thereby inducing a greater quantity; of air flow throughtherecirculating intake of the duct.

The specific details of a preferred embodiment of the invention, andtheir mode of functioning will be particularly pointed out in clear,concise and exact terms in conjunction with the accompanying drawings,wherein:

FIGURE 1 is a schematicview of a portion of an air conditioning systemin which a heat exchanger coil is arrangedto change the temperature ofan air stream flowing along a duct to two distribution points;

FIGURE 2 is a schematic elevational view of'a register maintaining-apredetermined mini-mum quantity .of air' a portion of an air FIGURE 3.

flow over the. heat'exchanger of the air conditioning sys-.

tern; and

FIGURE -'7 is a detail viewion an enlarged scale, of a.

further modification of means for maintaining a predetermined minimumquantity of air ,flow over the heat exchanger of the air conditioning,system.

Referring now more particularly to the drawings, like numerals in thevarious figures will be employed to designate like parts. As best seenin FIGURE 1, an" embodiment of the instant invention is illustrated inconnection with an air conditioning system which may be employed forheating or cooling a plurality of conditioned areas.

The system 10 comprises an air conditioning source in the form of a heatexchanger 11 arranged within supply duct 12 in heat exchangerelationship with the air flowing through the duct. A fan13 may beutilized in conventional fashion to induce air fiowthrough-filter 14 andthrough duct 12 which confines an air stream along. a flow path overheat exchanger 11 to the areas-to be conditioned. The heat exchanger '11is coupled to appropriate heating or cooling apparatus 15 which may beeither a;

furnace, or refrigeration system, as will be understood by those skilledin the art, depending on whether the air conditioning system is to beemployed for heating or cooling purposes. It will be further apparentthat the heat exchanger 11 may also be of a type which functionsalternatively as the. evaporator coil of a refrigeration system or thecondenser coil of the refrigerationsystem in which case apparatus 15will comprise a compressor and alternatively functioning heat exchangercoil along with the appropriate expansion mechanism, reverse valving andcontrols.

The supply duct 12 is shown to'extend to two conditioned areas A and B,it being understood that this is shown by way of example, and that thenumber of areas to which conditioned air is supplied may be varied asdesired and depending on the air handlingcapacities of satisfy aestheticrequirements, and to permit desired air. flow patterns to be obtained inthe conditioned area. A- bafiie plate or damper 25 is supported ondamper shaft 26, shaft 26 and damper 25 being suitably mounted forpivotal movement as seen in FIGURE 4. Damper 25 may be moved froma'lirniting position abutting stop member 28 and providing full flow ofair through outlet grill 21 when the damper 25 is to the right asviewed'in 'FIG- URE 4, to a non-flow position when the damper is to the7 living room E.

let so asto permit continued induction of roomair when damper 25 is inthe full open position. a

The register 20 is formed with a return air inlet 27 to the right ofdamper 25 as viewed in FIGURE 4.

Adjustment of the positionv of damper 25 ,is accomplished by the noveldamper mounting which includes. a novel yieldable spring clutch 30 shownschematically in Clutch 30 comprises a clutch plate 31 arranged overshaft 26 and rotatable freely with respect thereto. A clutch plate 32is'mounted for rotation with a control shaft 33 suitably supported forrotation in-bearings 35. A thumb screw 36 connects clutch plate 31 toclutch plate 32 for rotation therewith. Extending fro-m clutch plate 32is a detent 40 which is movable withthe clutch plate 32 into engagementwith a lug 41: formed on damper'shaft 26. 1A spring member 45, here,illustrated in the shape of'a conical coil, spring; is arranged betweenclutch plate 31'and damper shaft-26. .Spring 45 is wound around shaft 26and one end of the spring is anchored to move with clutch'plate 31 Whilethe other end of spring 45.is secured to a damper" shaft 26 for inFIGURE 6. Air conditioning system.60 comprisesa,

heat exchanger 61 arranged within main supply duct 62 in heat exchangerelationship with the air flowing through Fan 63 maybe utilized toinduce .air' through the duct, filter 64 and through main duct 62 toauxiliary ducts 65 and 66.- Heat exchanger 61 is coupled to appropriateheating or cooling apparatus 67, similar to apparatus 15 shown inFIGURE 1. 7

Supply duct 62 connects withauxiliary ducts 65 and 66 which communicatewith the areas E, F, G, H to be' conditioned. By way of illustration andnot limitation,

these areas may comprise the'living room, dining room, and bedrooms,respectively, in a dwelling.

Ordinarily, a thermostat .68 for controlling the operation of theapparatus 67 and fan 63 is provided in one ofthe first story rooms ofthe Within the areas F, G and H there are provided outlets 70 havingadjustable dampers 71 therein for modulating the air flow into each areaas desired. The dampers may be controlled manually or automatically asdesired.

In area E, outlet 73 is provided with a novel, register.

Openings 80, 81 and 82 may be defined within the outlet;

The register may be provided with a first manually adjustable damper 74,controlling flow-through opening '80, a second damper 76 responsive to apredetermined PICS? sure within supply duct 65 sensed by controller 76for V A modification of the means for controlling the air 7 flow throughoutlet 73is illustrated inFIGURE .7. this case, the outlet 73' may haveopenings 83 and .84.

An adjustable damper '85 controls the how of air through openings 83.Damper 185 may be either manually or automatically adjustable.

Damper 86 pivotally mounted on shaft is designed to perform thefunctions of both'dampers -76 rand;,7-7.

Secured to shaft 87 is a lever, 88 comprised of arms 95 and 96.Adjustably mounted on arm 95 is balance weight a 89. The balanceweight89 is connected to arm 95 by left as viewed in FIGURE 4. Baffle ordeflector 24' is 7 suitable fastening means, for example, set screw 90.Arm

96 is movable within elongated opening 91 in Weight: Thus, it isapparent that after a predetermined rotational movement of damper. 86,arm v96 of lever 88 will engage dwelling, as for example',,in the thetop of opening 91. Furthermovement of the damper is resisted until thepressure in the duct system is greater than the resistance provided bythe force of weight 92. Then weight 92 is raised from support 93 anddamper 86 is moved further toward the full open position to vent airinto the area served by outlet 73'.

Operation The aforedescribed novel register 20 finds particular utilityin connection with an air conditioning system having a plurality ofdistribution points for the conditioned air, remote from theconditioning source. Thus, in an air: conditioning system as illustratedin FIGURE 1 novel registers 20 are positioned at the conditioned areas Aand B remote from the conditioning source or heat exchanger 11.

The air flow from the conditioning source to the conditioned areas isgenerally obtained by means of fan 13. As is apparent to those skilledin the art, the quantities of air flowing in heat exchange relationshipwith heat exchanger 11 determine the heat [flow between the heatexchanger and the air stream. The heat exchange equipment is generallydesigned to operate within given temperature ranges so that in order toobtain given air conditioning temperatures the heat exchanger isdesigned of a given capacity to accommodate the heating and/ or coolingloads of the conditioned areas. Since the capacity of the heat exchangeequipment is such that maximum operating efficiency is obtained withingiven temperature ranges, it is desirable to insure the presence of airflow over the heat exchanger 11 so as to obtain these desiredtemperature ranges. Similarly, the air handling capacities of the duct12 and fan 13 are selected to provide desired design conditions.

Where an air conditioning system is installed in which the occupants ofindividual conditioned areas may selectively determine whetherconditioned air will be provided from the supply duct, it is necessaryto make certain that the adjustment of air supply in any one conditionedarea will not effect the operation of the air conditioning system to thedetriment of other areas. This is accomplished by the adjustableregister '20 of the present invention.

In use, the occupant of any given conditioned area, A or B asillustrated in FIGURE 1, may selectively determine the flow of air intothe conditioned area by adjusting control knob 55. Rotation of knob '55rotates pinion 54 which in turn acts on rack 53 to move same therebypulling on rod 51 which in turn pulls crank arm 50. The pull on crankarm '50 effects rotation of shaft 33 which moves detent 40 against lug41 causing shaft 26 to rotate with resulting movement of baffle 25.

When bafiie 25 is moved via the aforedescribed adjusting mechanism to aposition closing off the flow of air through register 20, as effected bymoving baffle 25 to the left as viewed in FIGURE 4, there will be areduction in the quantity of air flowing through the system. When thisflow of air drops beneath a desired design level, the spring 45 whichhas been preselected to yield under a stress indicating a pressure abovedesired design pressure in the supply duct 12. As a result of thisyielding, bafile 25 will move against the biasing action of spring 45towards the right as viewed in FIGURE 4, thereby increasing the flow ofair through register 20, notwithstanding the manual adjustment made bythe room occupant.

When it is desired to vary the preselected yield value of spring 45,thumb screw 36 may be loosened and clutch plates 31 and 32 may besuitably rotated With respect to one another. The thumb screw or othersuitable fastening means, as for example, a set screw, may then be movedto secure the plates 31 and 32 together.

It Will be observed that when the baffle plate is moved towards a closedposition, the increase in air velocity resulting from the constructionof flow through register 20 will-increase the quantity of .air inducedvia return air opening 27.

In FIGURE 5, the graph illustrates the static" pressure within the ductrequired to give desired air flow for design conditions-to obtain. Thus,as indicated on the graph, as the cubic. feet per minute of air flowthrough supply duct I12 increases, there is a proportionate drop in thestatic pressure in the duct. Points C and D on the curve illustrate adesired. design range within which the air flow through the duct workshould operate to obtain eflicient heat exchanger operation. Point Cindicates the optimum desired fan loading condition, and point Dindicates minimum conditions acceptable. Spring 45 is accordinglyselectedto yield under a pressure greaterthan that at point D so thatthe bafiie will open, or move to the right as indicated in FIGURE 4,thereby increasing duct air flow and bring the system within its desireddesign range.

The novel mechanism for controlling the air flow through outlet 73 inarea E functions to assure that the adjustment of the air supply in eachof a plurality of areas will not adversely efiect the operation of theair conditioning system.

Assume that each of the dampers 71 are adjusted so that the desiredquantity of air is passing over heating or cooling apparatus 67.Thermostat 68 controls the normal operation of apparatus 67 and fan 63.If one or more of the dampers -71 are closed, there is a reduced loadrequirement and the air supply over heat exchanger 16 may be adverselyaffected. The static pressure rise within the supply duct will be sensedby controller 76 which will actuate damper 76 toward the open position.If the duct pressure rises to a second predetermined level, controller78 will actuate damper 77 toward open position. The increased dischargeof air into area E will function to insure desired air flow over heatexchanger 61 and will also relatively quickly influence thermostat 68 toterminate fan and/ or heating or cooling apparatus operation.

The control mechanism shown in FIGURE 7 functions in a like manner tothat shown in FIGURE 6. Damper may be adjusted to permit a desired flowof air into area B. If one or more of the dampers in the other areas areclosed and the pressure rises undesirably in the supply duct, the damper86 will be pivoted toward open position. Rotational movement of thedamper will be stopped when lever arm 88 reaches the limit of the lostmotion connection provided by the opening'91 in weight 92 through whichthe lever arm 88 extends.

If .there is adequate air flow over heat exchanger 61, system operationwill again be controlled by thermostat 68. On the other hand, upon afurther rise in the static pressure above a predetermined value such aswill overcome the force exerted by weight 92, damper 86 will be pivotedtoward the full open position.

It is then seen that operation of an air conditioning system providedwith the present invention is enhanced. Improved means have beenprovided for controlling air distribution from a central conditioningpoint a variety of different distribution points with the control actionprovided at any one distribution point not adversely affecting theoperation of the conditioning equipment. Furthen there has 'beenprovided novel adjustable register means for use in an air distributionsystem in which manual adjustment of air discharge may be provided,

but individual adjustment may not function to cause the system tooperate in an improper manner.

While I have shown preferred embodiments of my invention, it is obviousthat other modifications will be apparent to persons skilled in the art,and I desired that my invention be limited only within the scope of theappended claims.

I claim:

1. In an air distribution system for supplying conditioned air to aplurality of zones to be conditioned, the

.7 V combination of a central station for conditioning air com-- prisinga heat exchanger, temperature responsive control means for controllingoperation of said central station, duct means communicating said centralstation with each zone to be conditioned, adjustable damper means forcontrolling the discharge of air from the duct means into the zones to:be treated, mechanism responsive to the attainment of preselectedpressure conditions within the duct means to vent the duct means to oneof said zones thereby maintaining a predetermined minimum.quan-tity ofair flow in heat exchange relationship with the heat exchanger in thecentral station, said rnechanism including rn'eans responsive to a firstpredetermined pressure condition in the duct means and a secondpredetermined pressure condition in the ductmeans to adjust said dampermeans,

said adjustable damper means including a first damper,

and a second damper, and said means including a first control to actuatethe first damper'in response to a first determined pressure in the ductmeans and a second controlto actuate the second damper in response to asecond predetermined pressure in the duct means.

2. In an air distribution system for supplying conditioned air to aplurality of zones to be conditioned, the combination of a centralstation for conditioning air comprising a heat exchanger, temperatureresponsive control means for controlling operation of said centralstation, duct means communicating said central station With each zone tobe conditioned, adjustable damper means for controlling the discharge ofair from the duct means into 8 the zones to be treated, first mechanismyieldable in response to a first determined pressure in the duct meanstoadjust said damper means and second mechanism yieldable in response to asecond determined pressure in the. duct means to further adjust saiddamper means, the damper means comprising a damper pivotally mounted ona shaft, the first mechanism including a lever secured to the shaftcomprising a first arm and a second arm, a balance weigh-t mounted onsaid first arm, and said second mechanism including a second balanceweight'having a slot therein receiving the second arm, the end of, the,"slot serving as a stop for movement of the second arm in the slotwhereby the first predetermined duct pressure applied to said damperrotates said lever until the second 1 15 arm engages the stop whileapplication of the, second pre- 1 determined duct pressure to saiddamper furtherrotatesg said lever. carrying the second balanceweightth'erewithQ References Cited by the Examiner UNITED STATES PATENTS5/1961 Waterfill 165-31 X 4/ 1965 I Ostrander l6516 X FOREIGN PATENTS1/1946 Great Britain. 4/1960 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

. M. ANTONAKAS, Assistant Examiner.

1. IN AN AIR DISTRIBUTION SYSTEM FOR SUPPLYING CONDITIONED AIR TO APLURALITY OF ZONES TO BE CONDITIONED, THE COMBINATION OF A CENTRALSTATION FOR CONDITIONING AIR COMPRISING A HEAT EXCHANGER, TEMPERATURERESPONSIVE CONTROL MEANS FOR CONTROLLING OPERATING OF SAID CENTRALSTATION, DUCT MEANS COMMUNCATING SAID CENTRAL STATION WITH EACH ZONE TOBE CONDITIONED, ADJUSTABLE DAMPER MEANS FOR CONTROLLING THE DISCHARGE OFAIR FROM THE DUCT MEANS INTO THE ZONES TO BE TREATED, MECHANISMRESPONSIVE TO THE ATTAINMENT OF PRESELECTED PRESSURE CONDITIONS WITHINTHE DUCT MEANS TO VENT THE THE DUCT MEANS TO ONE OF SAID ZONES THEREBYMAINTAINING A PREDETERMINED MINIMUM QUANTITY OF AIR FLOW IN HEATEXCHANGE RELATIONSHIP WITH THE HEAT EXCHANGER IN THE CENTRAL STATION,SAID MECHANISM INCLUDING MEANS RESPONSIVE TO A FIRST PREDETERMINEDPRESSURE CONDITION IN THE DUCT MEANS AND A SECOND PREDETERMINED PRESSURECONDITION IN THE DUCT MEANS TO ADJUST SAID DAMPER MEANS, SAID ADJUSTABLEDAMPER MEANS INCLUDING A FIRST DAMPER, AND A SECOND DAMPER, AND SAIDMEANS INCLUDING A FIRST CONTROL TO ACTUATE THE FIRST DAMPER IN RESPONSETO A FIRST DETERMINED PRESSURE IN THE DUCT MEANS AND A SECOND CONTROL TOACTUATE THE SECOND DAMPER IN RESPONSE TO A SECOND PREDETERMINED PRESSUREIN THE DUCT MEANS.